1. a School of Social Ecology , University of California at Irvine , Irvine , CA , USA
2. b School of Public Health , University of California at Berkeley , Berkeley , CA , USA
3. c School of Public Health , University of California at Berkeley , Berkeley , CA , USA
4. d Chemistry Department , Princeton University , Princeton , NJ , USA
5. e Aerosol Dynamics , Berkeley , CA , USA
6. f Electronically Monitored Ecosystems (EME) , Berkeley , CA , USA
7. g Pittsburgh Research Laboratory , National Institute for Occupational Safety and Health Centers for Disease Control and Prevention , Pittsburgh , PA , USA
8. h Aerosol Dynamics , Berkeley , CA , USA